Portal Revolution is probably the best Portal mod out there, and while I commend the effort, it is a bit disappointing in a couple of areas. Puzzles were pretty easy and simple all around, even if they were decently fun. The new mechanics didn't get enough time in the spotlight to feel fully utilized. And the story, while kinda fun, ends pretty abruptly with no fanfare. Other than all of that, the overall pacing was great and all the environments (while still very Portal 2) were kept unique and integrated in the Portal lore leading to a very "Portal 3" feeling game. If you've played Portal 2, give this a shot for a couple of hours of fun. For the great price of free, it deserves it.